[Qgis-user] Geolocating .flt files

[Andrew Harfoot]

Hi Gary,

Looking at your snippet of the hdr file, the dataset appears to be an ENVI raster see:
https://www.harrisgeospatial.com/docs/ENVIHeaderFiles.html

These rasters can be opened by QGIS (via GDAL as Richard states). The relevant notes are here:
https://www.gdal.org/frmt_various.html#EHdr

The fact that QGIS is loading the raster is good, but it may be that QGIS is also already reading the georeferencing data. A good way to check is to open the layer properties of the dataset and look under the Information tab. Here you should see various properties of the image reported, looking at the geo points info that you supplied, the CRS should be a geographic (Lat/Lon) system, and the extents will be roughly 145 to 148° W and 40 to 44° S (Tasmania?). Do the coordinates reported by QGIS match this? If so then it would appear that QGIS is reading the information in the hdr file correctly!

If the information isn't being read, one possibility is that the hdr file doesn't follow the naming convention that GDAL is expecting - if the image is called data.flt, then GDAL will expect the header file to be data.hdr, and not data.flt.hdr. If the latter, then try renaming  the file.

Cheers,

Andy

On 09/05/2019 10:31, Quinn, Gary wrote:
I am new to Qgis.

I have an .flt (floating point raster) file and an associated .hdr file.
I can import the .flt  image file into Qgis (using Add raster layer), and the image displays correctly.
But how do I geolocate this image using the associated .hdr file?
In other words, how do I make Qgis use the .hdr file to let me know the lat/lon of each pixel on the display?

Note: The .hdr file is like this:
geo points  = {     1,     1,  -40.212464,  146.355212,     1,  2590,  -44.006326,  145.100364,  1024,  2590,  -44.252673,  146.901021,  1024,     1,  -40.442148,  148.049722}

So I want Qgis to use this .hdr information to geolocate the image.
I have searched various info about using .flt images and geolocation but can't find anything.

Appreciate any help.

Thanks


--
Gary Quinn
Chief Engineer
ESS Weathertech www.essweather.com<https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.essweather.com&data=01%7C01%7CA.J.P.Harfoot%40soton.ac.uk%7C62a67ffb7e814f250cf208d6d4613f91%7C4a5378f929f44d3ebe89669d03ada9d8%7C0&sdata=QB%2F3vY9uqiVWaYG4Vx5R6O2pBFcB5bkhExA2pzrRUd4%3D&reserved=0>
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T +61 3 8420 8999 M +61 (0)418 307 118 Skype ess-gary.quinn



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--
Andy Harfoot

GeoData Institute
University of Southampton
Southampton
SO17 1BJ

Tel:  +44 (0)23 8059 2719

www.geodata.soton.ac.uk<http://www.geodata.soton.ac.uk>

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